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 * Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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 */

package javafx.scene.control.cell;

import javafx.beans.property.BooleanProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Node;
import javafx.scene.control.*;
import javafx.scene.layout.HBox;
import javafx.util.Callback;
import javafx.util.StringConverter;
import static javafx.scene.control.cell.CellUtils.createComboBox;

/**
 * A class containing a {@link TreeCell} implementation that draws a 
 * {@link ComboBox} node inside the cell.
 * 
 * <p>By default, the ComboBoxTreeCell is rendered as a {@link Label} when not 
 * being edited, and as a ComboBox when in editing mode. The ComboBox will, by 
 * default, stretch to fill the entire tree cell.
 * 
 * <p>To create a ComboBoxTreeCell, it is necessary to provide zero or more 
 * items that will be shown to the user when the {@link ComboBox} menu is 
 * showing. These items must be of the same type as the TreeView TreeItems, such 
 * that upon selection, they replace the existing value in the 
 * {@link TreeItem#valueProperty()}.
 * 
 * @param <T> The type of the TreeItems contained within the TreeView.
 * @since JavaFX 2.2
 */
public class ComboBoxTreeCell<T> extends DefaultTreeCell<T> {
    
    /***************************************************************************
     *                                                                         *
     * Static cell factories                                                   *
     *                                                                         *
     **************************************************************************/
    
    /**
     * Creates a ComboBox cell factory for use in {@link TreeView} controls. By 
     * default, the ComboBoxCell is rendered as a {@link Label} when not being 
     * edited, and as a ComboBox when in editing mode. The ComboBox will, by 
     * default, stretch to fill the entire tree cell.
     * 
     * @param <T> The type of the elements contained within the TreeView.
     * @param items Zero or more items that will be shown to the user when the
     *      {@link ComboBox} menu is showing. These items must be of the same 
     *      type as the TreeView<T>, such that upon selection, they replace the 
     *      existing value in the TreeItem {@link TreeItem#valueProperty() value} 
     *      property.
     * @return A {@link Callback} that will return a TreeCell that is able to 
     *      work on the type of element contained within the TreeView.
     */    
    @SafeVarargs
    public static <T> Callback<TreeView<T>, TreeCell<T>> forTreeView(T... items) {
        return forTreeView(FXCollections.observableArrayList(items));
    }
    
    /**
     * Creates a ComboBox cell factory for use in {@link TreeView} controls. By 
     * default, the ComboBoxCell is rendered as a {@link Label} when not being 
     * edited, and as a ComboBox when in editing mode. The ComboBox will, by 
     * default, stretch to fill the entire tree cell, excluding the space 
     * allocated to the tree cell indentation and disclosure node(i.e. the arrow).
     * 
     * @param <T> The type of the {@link TreeItem} elements contained within the 
     *      TreeView.
     * @param items An {@link ObservableList} containing zero or more items that 
     *      will be shown to the user when the {@link ComboBox} menu is showing. 
     *      These items must be of the same type as the TreeView generic type, 
     *      such that upon selection, they replace the existing value in the 
     *      {@link TreeItem} that is being edited (as noted in the 
     *      {@link TreeView#editingItemProperty()}.
     * @return A {@link Callback} that will return a TreeCell that is able to 
     *      work on the type of element contained within the TreeView.
     */
    public static <T> Callback<TreeView<T>, TreeCell<T>> forTreeView(
            final ObservableList<T> items) {
        return forTreeView(null, items);
    }
    
    /**
     * Creates a ComboBox cell factory for use in {@link TreeView} controls. By 
     * default, the ComboBoxCell is rendered as a {@link Label} when not being 
     * edited, and as a ComboBox when in editing mode. The ComboBox will, by 
     * default, stretch to fill the entire tree cell.
     * 
     * @param <T> The type of the elements contained within the TreeView.
     * @param converter A {@link StringConverter} to convert the given item (of 
     *      type T) to a String for displaying to the user.
     * @param items Zero or more items that will be shown to the user when the
     *      {@link ComboBox} menu is showing. These items must be of the same 
     *      type as the TreeView<T>, such that upon selection, they replace the 
     *      existing value in the TreeItem {@link TreeItem#valueProperty() value} 
     *      property.
     * @return A {@link Callback} that will return a TreeCell that is able to 
     *      work on the type of element contained within the TreeView.
     */  
    @SafeVarargs
    public static <T> Callback<TreeView<T>, TreeCell<T>> forTreeView(
            final StringConverter<T> converter, 
            final T... items) {
        return forTreeView(converter, FXCollections.observableArrayList(items));
    }
    
    /**
     * Creates a ComboBox cell factory for use in {@link TreeView} controls. By 
     * default, the ComboBoxCell is rendered as a {@link Label} when not being 
     * edited, and as a ComboBox when in editing mode. The ComboBox will, by 
     * default, stretch to fill the entire tree cell.
     * 
     * @param <T> The type of the elements contained within the TreeView.
     * @param converter A {@link StringConverter} to convert the given item (of 
     *      type T) to a String for displaying to the user.
     * @param items An {@link ObservableList} containing zero or more items that 
     *      will be shown to the user when the {@link ComboBox} menu is showing. 
     *      These items must be of the same type as the TreeView generic type, 
     *      such that upon selection, they replace the existing value in the 
     *      {@link TreeItem} that is being edited (as noted in the 
     *      {@link TreeView#editingItemProperty()}.
     * @return A {@link Callback} that will return a TreeCell that is able to 
     *      work on the type of element contained within the TreeView.
     */  
    public static <T> Callback<TreeView<T>, TreeCell<T>> forTreeView(
            final StringConverter<T> converter, 
            final ObservableList<T> items) {
        return list -> new ComboBoxTreeCell<T>(converter, items);
    }
    
    
    
    /***************************************************************************
     *                                                                         *
     * Fields                                                                  *
     *                                                                         *
     **************************************************************************/      
    private final ObservableList<T> items;

    private ComboBox<T> comboBox;
    private HBox hbox;
    

    
    /***************************************************************************
     *                                                                         *
     * Constructors                                                            *
     *                                                                         *
     **************************************************************************/   
    
    /**
     * Creates a default ComboBoxTreeCell with an empty items list.
     */
    public ComboBoxTreeCell() {
        this(FXCollections.<T>observableArrayList());
    }
    
    /**
     * Creates a default {@link ComboBoxTreeCell} instance with the given items
     * being used to populate the {@link ComboBox} when it is shown.
     * 
     * @param items The items to show in the ComboBox popup menu when selected 
     *      by the user.
     */
    @SafeVarargs
    public ComboBoxTreeCell(T... items) {
        this(FXCollections.observableArrayList(items));
    }
    
    /**
     * Creates a {@link ComboBoxTreeCell} instance with the given items
     * being used to populate the {@link ComboBox} when it is shown, and the 
     * {@link StringConverter} being used to convert the item in to a 
     * user-readable form.
     * 
     * @param converter A {@link StringConverter} that can convert an item of 
     *      type T into a user-readable string so that it may then be shown in 
     *      the ComboBox popup menu.
     * @param items The items to show in the ComboBox popup menu when selected 
     *      by the user.
     */
    @SafeVarargs
    public ComboBoxTreeCell(StringConverter<T> converter, T... items) {
        this(converter, FXCollections.observableArrayList(items));
    }
    
    /**
     * Creates a default {@link ComboBoxTreeCell} instance with the given items
     * being used to populate the {@link ComboBox} when it is shown.
     * 
     * @param items The items to show in the ComboBox popup menu when selected 
     *      by the user.
     */
    public ComboBoxTreeCell(ObservableList<T> items) {
        this(null, items);
    }

    /**
     * Creates a {@link ComboBoxTreeCell} instance with the given items
     * being used to populate the {@link ComboBox} when it is shown, and the 
     * {@link StringConverter} being used to convert the item in to a 
     * user-readable form.
     * 
     * @param converter A {@link StringConverter} that can convert an item of 
     *      type T into a user-readable string so that it may then be shown in 
     *      the ComboBox popup menu.
     * @param items The items to show in the ComboBox popup menu when selected 
     *      by the user.
     */
    public ComboBoxTreeCell(StringConverter<T> converter, ObservableList<T> items) {
        this.getStyleClass().add("combo-box-tree-cell");
        this.items = items;
        setConverter(converter != null ? converter : CellUtils.<T>defaultStringConverter());
    }
    
    
    
    /***************************************************************************
     *                                                                         *
     * Properties                                                              *
     *                                                                         *
     **************************************************************************/
    
    // --- converter
    private ObjectProperty<StringConverter<T>> converter = 
            new SimpleObjectProperty<StringConverter<T>>(this, "converter");

    /**
     * The {@link StringConverter} property.
     */
    public final ObjectProperty<StringConverter<T>> converterProperty() { 
        return converter; 
    }
    
    /** 
     * Sets the {@link StringConverter} to be used in this cell.
     */
    public final void setConverter(StringConverter<T> value) { 
        converterProperty().set(value); 
    }
    
    /**
     * Returns the {@link StringConverter} used in this cell.
     */
    public final StringConverter<T> getConverter() { 
        return converterProperty().get(); 
    }
    
    
    // --- comboBox editable
    private BooleanProperty comboBoxEditable = 
            new SimpleBooleanProperty(this, "comboBoxEditable");

    /**
     * A property representing whether the ComboBox, when shown to the user,
     * is editable or not.
     */
    public final BooleanProperty comboBoxEditableProperty() { 
        return comboBoxEditable; 
    }
    
    /** 
     * Configures the ComboBox to be editable (to allow user input outside of the
     * options provide in the dropdown list).
     */
    public final void setComboBoxEditable(boolean value) { 
        comboBoxEditableProperty().set(value); 
    }
    
    /**
     * Returns true if the ComboBox is editable.
     */
    public final boolean isComboBoxEditable() { 
        return comboBoxEditableProperty().get(); 
    }
    
    
    
    /***************************************************************************
     *                                                                         *
     * Public API                                                              *
     *                                                                         *
     **************************************************************************/
    
    /**
     * Returns the items to be displayed in the ChoiceBox when it is showing.
     */
    public ObservableList<T> getItems() {
        return items;
    }     
    
    /** {@inheritDoc} */
    @Override public void startEdit() {
        if (! isEditable() || ! getTreeView().isEditable()) {
            return;
        }

        TreeItem<T> treeItem = getTreeItem();
        if (treeItem == null) {
            return;
        }

        if (comboBox == null) {
            comboBox = createComboBox(this, items, converterProperty());
            comboBox.editableProperty().bind(comboBoxEditableProperty());
        }
        if (hbox == null) {
            hbox = new HBox(CellUtils.TREE_VIEW_HBOX_GRAPHIC_PADDING);
        }
        
        comboBox.getSelectionModel().select(treeItem.getValue());
        
        super.startEdit();

        if (isEditing()) {
            setText(null);

            Node graphic = CellUtils.getGraphic(treeItem);
            if (graphic != null) {
                hbox.getChildren().setAll(graphic, comboBox);
                setGraphic(hbox);
            } else {
                setGraphic(comboBox);
            }
        }
    }

    /** {@inheritDoc} */
    @Override public void cancelEdit() {
        super.cancelEdit();
        
        setText(getConverter().toString(getItem()));
        setGraphic(null);
    }
    
    /** {@inheritDoc} */
    @Override public void updateItem(T item, boolean empty) {
        super.updateItem(item, empty);
        
        Node graphic = CellUtils.getGraphic(getTreeItem());
        CellUtils.updateItem(this, getConverter(), hbox, graphic, comboBox);
    };
}
